Mot emissions failure

[blaze_away]

Failed as follows
Fast idle 2500 rpm
CO 0.9% Limit 0.3%
HC 220 ppm Limit 200ppm

2nd Fast idle 2500 rpm
CO 1.18 Limit 0.3%
HC 676ppm Limit 200 ppm

Natural idle
CO 0.08% Limit 0.50%

4.6 with new 400 cell euro 3 main cat 1000 miles ago. 20am MAF stealth cam.
Well maintained new plugs BPR6ES, no extender, Rover Gauge shows
Long term trim 5% and 4% left and right
Short term oscillating around zero

Any suggestions on what to check/do to get these in control ?
I am thinking new air filter and oil change then what else ?

[Belle427]

I would think if its running well then you have to look at the cat, not sure which one you have but was it nice and hot when tested?
What was the Lambda reading?

Edited by Belle427 on Friday 7th March 19:11

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Belle427 said:

I would think if its running well then you have to look at the cat, not sure which one you have but was it nice and hot when tested?
What was the Lambda reading?

Edited by Belle427 on Friday 7th March 19:11

Not sure of cat maker but was fitted by highly regarded exhaust fabricator.
Yep it was hot
Lambda were 1.01 and 1.05

[Loubaruch]

You probably know this already but the standard 3 cat Griffith 500 in good fetlle has extremely low CO and HC figures. My MOT station always comments how low the figures are and further remarks that the figures are lower than most 3 year old cars presented for test.

[Belle427]

Lambda suggests it may be on the lean side, im not sure what this needs to be to enable the cat to work efficiently.
No expert on emissions sorry so maybe someone else can comment.

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Belle427 said:

Lambda suggests it may be on the lean side, im not sure what this needs to be to enable the cat to work efficiently.
No expert on emissions sorry so maybe someone else can comment.

Me too, not sure what to make of it. I assumed that as it's on map 5 and lambda are swit hing then it's controlling as it should. Looks like I'm wrong unfortunately

[Belle427]

High CO and HC suggests rich but Lambda suggests lean, just wondering if you have an exhaust leak somewhere thats making the Lambda lean and confusing.
Not sure how much you have used the car since last Mot, i would do as you suggest and give it a small service, check the plugs and maybe add an emissions treatment to the tank and take it for a good thrash one day.
https://www.walkerexhaust.com/support/tech-tips/fi...

Edited by Belle427 on Saturday 8th March 07:58

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Belle427 said:

High CO and HC suggests rich but Lambda suggests lean, just wondering if you have an exhaust leak somewhere thats making the Lambda lean and confusing.
Not sure how much you have used the car since last Mot, i would do as you suggest and give it a small service, check the plugs and maybe add an emissions treatment to the tank and take it for a good thrash one day.
https://www.walkerexhaust.com/support/tech-tips/fi...

Edited by Belle427 on Saturday 8th March 07:58

Great stuff thank you. I will also put timing back to more standard as currently running "full vacuum" not ported.

[Belle427]

That can affect things for sure.

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Belle427 said:

That can affect things for sure.

Yeah that was a dummy mistake, just forgot I'd gone full vacuum.

[Belle427]

I think it's mentioned in the god damn shunt is killing me thread it will fail the emissions with it on full vacuum.

[Pagey430]

May be an Italian tune up is needed

Edited by Pagey430 on Saturday 8th March 14:49

[PabloGee]

I run mine on full vacuum, but will absolutely switch it back to ported for MOT day.
I keep the hose in the glovebox pouch for safe keeping.

[blaze_away]

Belle427 said:

I think it's mentioned in the god damn shunt is killing me thread it will fail the emissions with it on full vacuum.

Yes I am a dimwit.

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Pagey430 said:

May be an Italian tune up is needed

Edited by Pagey430 on Saturday 8th March 14:49

Would do, but no mot means I can't take it out.

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PabloGee said:

I run mine on full vacuum, but will absolutely switch it back to ported for MOT day.
I keep the hose in the glovebox pouch for safe keeping.

Good to know. I'll be switching g it back for retest.